The present invention relates generally to systems for communication with and for monitoring the locations of mobile, remote objects, including people. More particularly, the present invention relates to a system for locating and communicating with the objects (including people) without burdening the monitored object with heavy or bulky communications equipment.
Prior art systems illustrate the various needs for the present invention and that those efforts only partially meet these needs. For example, house arrest systems continuously monitor persons sentenced to remain within a defined, restricted area to assure they do in fact remain within the permitted area. These systems offer continuous oversight but suffer from being able to monitor the offender only at a single fixed location, e.g., his home.
Other prior art prisoner monitoring systems attempt to accommodate the offender sentenced to remain principally within one area but is allowed to travel to a second area during limited times, e.g., the offender must remain at her home except during working hours when she may travel to her place of business. However, these systems are not able to continuously monitor the offender and have limited monitoring areas or distances.
Another type problem exists regarding the need to quickly recover stolen vehicles. Certain type vehicles or assets, known as favorite targets of car thiefs, may have installed vehicle tracking systems. These vehicle tracking systems, powered by the vehicle's battery and not unduly limited in size or transmission power capability, allow authorities to track the location of the vehicle over an extended range and for an extended period of time. Such systems, however, do not notify the owner that the vehicle has been stolen and the vehicle is often transported out of the searchable area or disassembled before the theft is discovered and the recovery system activated. A need is therefore present to promptly notify the vehicle owner that the vehicle has been stolen.
In a similar fashion, an automated notification system is needed to notify the proper authorities when an asset has been moved from a given location. For example, in banks it is known to hide a small explosive device coupled with a permanent dye within one or more bundles of currency. When the dye-carrying bundle is removed from the bank, a signal is provided to the explosive device causing it to detonate, spewing the dye upon the currency and persons nearby. One problem with such devices is the fact that innocent passers-by may be injured by the impact from the explosion and the fact that the thief may become more violent in response to the explosion. Accordingly, it is desireable to use a proximity locating device within such currency bundles. The passage of the proximity device outside the range of a base unit could be made to cause an alarm to be signaled at the appropriate authorities and, if desired, to initiate geolocating the locating device within the currency bundle, all without alerting the thief or causing explosions in the vicinity of potentially innocent persons.
U.S. Pat. No. 4,918,432 to Pauley, et al. for a "House Arrest Monitoring System" illustrates a prior art system wherein the monitored individual's movement is limited to a single fixed area. Pauley, et al. discloses a system comprising an small transmitter in the form of an identification tag which is worn by the monitored individual and which transmits a periodic signal directly to a Field Monitoring Device (FMD) or, if the fixed area has communication dead spots, via a repeater to the FMD. The FMD then communicates to a central, fixed location, e.g., by modem and telephone line, to notify the central location when the monitored individual leaves or re-enters the monitored area. If the monitored individual leaves the fixed area, the central location is not aware of the individual's location. Disadvantageously, no provision is made for the central location to communicate with the individual or the individual to communicate with the central location. Such features are necessary if the system is being used to monitor and communicate with an individual who is under protective custody such that they must be able to freely move about without carrying heavy, bulky equipment and such that they must be in ready contact with central monitoring site to transmit or receive a panic signal.
U.S. Pat. No. 5,461,390 to Hoshen for a "Locator Device Useful for House Arrest and Stalker Detection" illustrates a prior art effort to provide intermittent mobile monitoring of an individual by periodically contacting and determining the location of a locator device attached to the individual in the form of a small transceiver strapped to the individual's leg. The central location initiates a monitoring cycle by transmitting a polling signal, via a wireless, e.g., cellular, system to the locator. Upon receipt of the polling signal, the locator queries a positioning system to ascertain its current location and transmits the location back to the central computer. The central computer then completes the monitoring cycle by comparing the individual's location against database records to determine if the individual is within an authorized location. While this system offers a degree of mobility for the monitored individual, requirements to keep the locator device small and lightweight, mandate compromises in transmission distances and frequency with which the locator can be polled. Therefore, continuous monitoring by the central location and communications at greater distances from the wireless transmission points between the central location and the locator device are not possible.